Open figure viewer
From the earliest time, guards have been used to control access to certain areas. Guards are people and, however conscientious, they are forgetful, bribable, coercible or just plain inefficient. The introduction of the key and lock provided the first automated assistance to control access and, despite the ingenuity of locksmiths, keys can be stolen, duplicated or lost and locks can be picked.
This content is only available via PDF.
© MCB UP Limited
1992
You do not currently have access to this content.
